Industrial robots have become an indispensable part of modern manufacturing. Robots perform many manufacturing tasks tirelessly, in hostile environments, and with high precision and repeatability.
In many robotic manufacturing applications, it is cost-effective to utilize a relatively generic robot arm to accomplish a variety of tasks. In these applications, a tool changer is used to attach different tools to the robot. One half of the tool changer, called the master unit, is permanently affixed to a robot arm. The other half, called the tool unit, is affixed to each tool that the robot may utilize. When the robot arm positions the master unit adjacent a tool unit connected to a desired tool, a coupling mechanism is actuated that mechanically locks the master and tool units together, thus affixing the tool to the end of the robot arm.
Robotic tool changer coupling mechanisms may be powered and automatic (i.e., operated under software control), or may be manually actuated. In many cases, manually actuated tool changers are preferred, as they may have lower cost and higher reliability than powered tool changers, as well as obviating the need for electrical power or pneumatic fluid on the robot arm. Additionally, applications such as food preparation or robotic surgery require that the entire system—including the tool changer—be “washable,” or capable of being easily sanitized, such as by dousing with antimicrobial fluid. In these applications, a design in which the coupling mechanism may be sealed against fluid intrusion is highly desirable.
A major concern in robotic manufacturing is safety. For example, ISO 13849, “Safety of machinery—Safety related parts of control systems,” defines five Performance Levels, denoted A through E. Performance Level D (PLD), mandated for many industrial robotics applications, requires a probability of less than 10−6 dangerous failures per hour—that is, at least a million hours of operation between dangerous failures. For a robotic tool changer, a dangerous failure would be the tool unit decoupling and separating from the master unit while in operation, resulting in dropping the attached tool. Accordingly, a robotic tool changer having a feature that positively locks it into a coupled state, and which minimizes or eliminates the probability of master and tool unit separation, is highly desirable.
The Background section of this document is provided to place embodiments of the present invention in technological and operational context, to assist those of skill in the art in understanding their scope and utility. Approaches described in the Background section could be pursued, but are not necessarily approaches that have been previously conceived or pursued. Unless explicitly identified as such, no statement herein is admitted to be prior art merely by its inclusion in the Background section.